Our 10-Year Experience with Atrial Myxomas: Is Concurrent Valve Intervention Really Warranted?

Introduction Primary cardiac myxomas are rare tumors. Concurrent valvular lesion is a common finding on evaluation which is thought to be due to annular dilatation secondary to tumor movement across the valve, functional obstruction across the valve, and severe pulmonary hypertension secondary to chronic obstruction. A common belief among surgeons is that excision of myxoma leads to abatement of symptoms, and further valve intervention may not be warranted. Methods A 10-year retrospective descriptive study was designed to analyze patients who underwent excision of cardiac myxoma at our center. Data was analyzed regarding presenting features, echocardiographic findings of myxoma and valve morphology, intraoperative assessment, and postoperative outcome with/without valve repair/replacement in all patients. Results A total of 22 patients underwent surgery for myxoma. Six patients underwent successful mitral valve repair with ring annuloplasty, two had moderate mitral regurgitation, three had severe mitral regurgitation, and one patient had no mitral regurgitation on preoperative assessment, but moderate mitral regurgitation was found intraoperatively. Four of these patients had no residual mitral regurgitation in follow-up period while two had mild residual mitral regurgitation. One patient had severe mitral stenosis of concurrent rheumatic etiology and successfully underwent mitral valve replacement. Conclusion Cardiac myxomas are rare benign tumors commonly associated with mitral valve insufficiency. Mitral valve should be assessed intraoperatively after excision of mass as preoperative assessment might often be insufficient. Concomitant mitral valve intervention might be needed with a case-specific tailored approach, and mitral valve repair with ring annuloplasty offers best surgical outcome in such cases.


INTRODUCTION
Primary cardiac myxomas are rare tumors [1] .Myxomas arise from pluripotent mesenchymal stem cells and are most commonly located in the left atrium.Concurrent involvement of mitral valve is a common finding on evaluation which is due to annular dilatation secondary to tumor movement across the valve, functional obstruction across the valve, and severe pulmonary hypertension secondary to chronic obstruction [2] .Despite this, excision of myxoma often leads to abatement of symptoms, and further valve intervention may not be warranted [3] .The objective of this study is to retrospectively analyze our center's specific experience over a period of 10 years in handling cardiac myxoma and the need for concurrent valvular repair/replacement with excision of myxoma.We also aim to correlate preoperative and intraoperative assessment of valve function to establish a correlation between valve disease severity and the intervention needed.

METHODS
A retrospective descriptive study was designed to analyze patients who underwent excision of cardiac myxoma at our tertiary care center at Atal Bihari Vajpayee Institute of Medical Sciences and Dr Ram Manohar Lohia Hospital (New Delhi, India) from May 2012 to December 2022.A total of 22 patients underwent surgical excision of cardiac myxoma in given time.Data was analyzed regarding presenting features, echocardiographic findings of myxoma and valve morphology, intraoperative assessment, and postoperative outcome with/without valve repair/replacement in all patients.

Surgical Technique
All procedures were conducted via median sternotomy and vertical pericardiotomy, with systemic heparinization and total cardiopulmonary bypass with aorto-bicaval cannulation and antegrade cold cardioplegic arrest.Cavae snugged.Myxomas were excised via right or left atriotomy with 5-mm free margin of interatrial septum sent for histopathology (Figure 1).The surgical approach was tailored in accordance with site of attachment of myxoma to interatrial septum or atrial chamber, surgeon's preference, and size of left atrium.In all cases, mitral valve was evaluated with aid of on-table transesophageal echocardiogram (TEE) and intraoperatively by visual assessment with segmental analysis of leaflets as well as saline insufflation into left ventricle through mitral valve.In six out of 22 patients, a trans left atrial (LA) approach was used, and mitral valve was assessed directly.
Eleven patients underwent a bi-atrial repair, and mitral valve was assessed directly in them as well through the LA approach.Five patients underwent a trans right atrial (RA) repair.In these patients, a transseptal approach to mitral valve was used after excision of myxoma.In such patients, if repair of mitral valve was indicated after saline testing, transseptal incision was extended superiorly towards roof of the left atrium while inferiorly it was extended towards inferior vena cavae, and repair was performed.Interatrial septum was closed directly or with a patch.Rewarming was started.Chambers were closed.Cross-clamp was removed.Patient was gradually weaned off cardiopulmonary bypass.

RESULTS
A total of 22 patients (Table 1) underwent surgery for myxoma from May 2012 to December 2022.Median age of the group was 34.5 years.And male to female ratio is 9:13, showing female preponderance for LA myxoma.Echocardiographic findings in relation to mitral valve were: six patients were found to have moderate mitral regurgitation (MR), three patients were reported to have severe MR (Figure 2), and one patient was reported to have severe mitral stenosis.Echocardiographic findings in relation to tricuspid valve were: one patient was reported to have moderate tricuspid regurgitation (TR), and four patients were reported with severe TR.
Trans LA approach was used in six patients while a bi-atrial approach was used in 11 patients.A trans RA approach was used in five patients.
Intraoperatively, out of six patients reported to have moderate MR, three patients (50%) were found to have normal mitral valve leaflet, subvalvular apparatus, and annulus size after excision of myxoma.The findings were confirmed on saline insufflation test and subsequently on intraoperative TEE after weaning off bypass.These patients did not undergo any concurrent valvular intervention.They had no MR on serial postoperative echocardiographic evaluation as well.
The remaining three patients with moderate MR underwent successful mitral valve repair with ring annuloplasty (Figure 3).Two of these patients had no residual MR in follow-up period while one had mild residual MR successfully managed by medical therapy.Three patients were reported to have severe MR on preoperative echocardiographic evaluation.Intraoperatively, mitral valve was evaluated with saline insufflation into the left ventricle followed by segmental analysis of anterior and posterior leaflets with a nerve hook.All three patients had dilated mitral valve annulus.Two of these patients had commissural leaks which were managed by commissuroplasty with 5.0 Prolene® sutures.Among them, one patient had additional posterior mitral leaflet (PML) scallop leak which was managed by scallop closure with 5.0 Prolene® suture.

Follow-up
All patients were routinely followed up -weekly follow-up for six weeks, monthly follow-up for six months, and half-yearly follow-up thereafter.successful De Vega's repair was carried in two of these patients, ring annuloplasty was carried out in one patient, while a posteroseptal commissuroplasty was carried out in one patient to control TR.
In the postoperative period, while three patients had mild TR in follow-up, one patient had moderate TR, which was managed successfully by fluid restriction and diuretics and needed no further surgical intervention.

DISCUSSION
Myxomas are the most prevalent primary cardiac tumors, with 80-85% found in the left atrium [4] .The common age group for cardiac myxoma is the third to fifth decade of life.Female sex is more commonly affected by this disease subset as evident by findings of our study as well [5,6] .The tendency of MR and prolapse is common in LA myxomas due to pendulum-like motion of myxomatous mass across mitral valve in each cardiac cycle leading to annular dilatation and leaflet prolapse [7] .This can also lead to complications such as endocarditis, atrial fibrillation, thromboembolism, and pulmonary hypertension, thus warranting a timely intervention [8] .An extensive preoperative and intraoperative mitral valve assessment is needed to evaluate valve dynamics, geometry, and valvular and subvalvular apparatus to classify functional MR [9,10] .A bi-atrial surgical approach is helpful to determine the correct resection margin by confirming the tumor pedicle under direct visualization, to minimize handling of the tumor, through evaluation of all heart chambers and to evaluate mitral valve completely [11] .
As evident from our study, 50% of the patients reported to have moderate MR did not need any concurrent valvular intervention after excision of myxoma.These patients did not have any residual MR as well in follow-up period.The remaining 50% of patients were successfully managed by mitral valve repair with ring annuloplasty.
In those patients diagnosed with severe MR (three patients), a successful mitral valve repair with ring annuloplasty/pericardial patch annuloplasty was carried out, thus obviating the need for valve replacement.Valve replacement was carried out in a single patient with stenotic mitral valve with rheumatic etiology.
In one of the first case reports of LA myxoma causing mitral incompetence, Blanco et al. managed to repair PML and performed an annuloplasty to limit postoperative mitral incompetence [12] .
Myxomas are a rare entity, and myxomas associated with valvular incompetence are further rarer; there lies a lack of detailed studies and evidences for recommendations for concurrent valvular intervention in such cases [13] .In the landmark study published by Lee et al. [1] discussing their 30-year experience with atrial myxomas, 5.3% (five out of 93) of patients operated for myxomas needed concurrent mitral valve intervention.While a valve replacement was carried out primarily in three out of five patients, two patients were managed by valve repair in their study.
The limited literature on cardiac myxoma advises for tailored approach for each individual patient reported to have concurrent mitral valve intervention.While moderate MR might not need any intervention after excision of myxomatous mass, an intervention of mitral repair is almost always a complete solution thus obviating a need for surgical valve replacement [14] .Surgeons' tailored approach with careful native valve preservation shall give optimum valvular incompetence relief to patient [15] .

Limitations
The limitations of our study are it being a retrospective analysis and the limited number of patients owing to rarity of this disease.

CONCLUSION
Cardiac myxomas are rare benign tumors commonly associated with mitral valve insufficiency.A thorough assessment of the mitral valve intraoperatively, with respect to valve morphology and subvalvular apparatus, after excision of mass is imperative as preoperative assessment might often be insufficient.Concomitant mitral valve intervention might be needed in case-specific tailored approach, and various mitral valve repair techniques with a ring annuloplasty can be implemented to achieve optimal surgical outcome.

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